Constraints on binary neutron star ejecta mass using NR simulations and GW170817 equations of state

Neutron star mergers have recently become a tool to study extreme gravity, nucleosynthesis, and the chemical composition of the Universe in a new way.  In order to accurately identify electromagnetic signals of neutron star mergers, both in the future and retroactively, better constraints on their merger signatures are required.  We compare a series of analytical models for dynamical ejecta as well as disk ejecta to see where they provide strong constraints on the amount of ejected mass expected from a system.  We also examine 2396 neutron star equations of state (EOS) to see whether a given ejecta mass could be reasonably produced with a NS of said EOS, and whether different ejecta models provide consistent predictions.  This is done to see if the observation of a specific neutron star merger can be used to rule out certain equations of state.  In our study, we vary the errors associated with the dynamical ejecta, disk mass ejecta, and ejected disk mass fraction to determine the primary source of uncertainty in the models we've considered.  We find that the difference between models is often comparable to or larger than the error associated with the models themselves, implying better constraints on the models are needed.